The 15th-century pope Pius II, who really initiated the modern discourse on "Europe", wrote a famous letter to Sultan Mohammad II, the conqueror of Constantinople, in which he celebrated the manifold powers of the old continent: "Spain so steadfast, France so warlike, Germany so populous, Britain so strong, Poland so daring, Hungary so active and Italy so rich, high-spirited and experienced in the art of war."

Now as then, Europe is unthinkable without its nations. To see Europe only as the European Union and its Brussels institutions is like describing a beautiful old house by reading out the instruction books for its plumbing, electrical system and central heating. To be sure, Europe is much more than the sum of its nations – but without them, it is nothing. So it is appropriate that when the Guardian launches a month of special European coverage on Monday, it will do so by looking in depth, week by week, at four nations mentioned by Pius II more than five centuries ago: Germany, France, Spain and Poland.

Meanwhile, let us consider Pius II's own nation, Italy, which celebrates the 150th anniversary of its supposed unification into a modern nation-state next Thursday – the Kingdom of Italy having been proclaimed on 17 March 1861. Italy is the ur-European country. Nowhere else can you find so many closely piled layers of European history. Only in Rome can you have lunch near the place where Julius Caesar was murdered, then pop over to hear St Peter's heir proclaim his 2,000-year-old message to the city and the world. Most of what made the traditional, early modern identity of Europe – especially the heritage of ancient Greece and Christianity – came to us through ancient Rome. Europe: from Julius Caesar to Silvio Berlusconi.

Every European country is unique, yet they all have much in common with each other and each part tells us something about the whole. Here are eight things that I think today's Italy tells us about today's Europe.

1. Italy, like Europe, Europe like Italy, does not know what story it wants to tell. A celebration of the 150th anniversary of "Italian unity" that I recently attended at its embassy in London was devoted almost entirely to two closely related themes: women and love. The evening was delightful, with Greta Scacchi reading some luminous verses from Dante's Divine Comedy (Amor, ch'a nullo amato amar perdona) and a tenor singing Neapolitan love songs till he seemed fit to burst. But it was a slightly odd way for a modern European country to present itself to its friends. As for the European Union, it can't even give us the songs.

2. Instead of a story, Europe presents a lifestyle. Italy is the most glorious exemplar of that lifestyle – food, wine, fashion, sun, "social" working hours and long holidays, bella figura, dolce vita and all that. The trouble is that this lifestyle is enjoyed only by a dwindling number of Italians and Europeans. It is unsustainable without radical economic and welfare state reform, and the successful liberal integration of men and women of migrant origin, many of them Muslims. (Pius II must be turning in his grave.)

3. Most Europeans, and many outside Europe, probably know more about Berlusconi than they do about any other European politician. He is the closest thing we have to a pan-European political figure. Unfortunately, what everyone knows about him is mainly baroque, salacious or unpleasant – to put it no more strongly. So instead of a proper drama of European politics as part of a well-functioning European public sphere, we have this tawdry operetta.

4. The range of what actually happens in countries inside the European Union is far wider and less attractive than the nice stories that we tell ourselves and the rest of the world. Berlusconism is not fascism, but it is also a long way from the ideal type of a well-functioning social liberal democracy that Europeans routinely claim is characteristic of Europe.

Italy is by no means alone in this. Viktor Orbán's Hungary – to take another old European country mentioned by Pius II – is chasing hard on its heels. If you were to combine in one imaginary country all the worst features of the 27 individual European Union member states, you'd have a pretty nasty place.

5. The moment when European countries have to be on their best liberal democratic law-abiding behaviour is in the year or two before they join the European Union. Once you are in, you can get away with murder. (I use the phrase in its loose, colloquial English sense.) If Berlusconi's Italy had to apply to join the union today, it might not be admitted.

6. One must never conflate the current government of a country with the country it claims to govern. All European countries have different elements within them, and Italy is more disparate than any. There are large areas of its national life – including many run by people who have supported Berlusconi – which are modern, effective, civilised and admirable. The same country that gives us the Emperor Silvio also gives us by far the most credible of the current candidates for governor of the European Central Bank. I mean, of course, Mario Draghi, Governor of the Bank of Italy.

7. We must not confuse enduring, historic nations with stable, united nation states. In The Pursuit of Italy, a book published to coincide with this anniversary, David Gilmour argues that Italy has spent 150 years precisely not becoming an effective, united nation state. He reminds us that supporters of Umberto Bossi's Northern League would jibe that "Garibaldi did not unite Italy; he divided Africa". If the political weakening of Berlusconi now means the strengthening of Bossi, this hardly bodes well for a more integrated Italy.

And there's a broader European point here. It's precisely the integration of the European Union that allows the self-indulgence of national disintegration. You only have to look at Belgium – without a government now for 270 days because of apparently irreconcilable differences between northern (Flemish, Dutch-speaking) and southern (Walloon, French-speaking) politicians.

8. Talking of Africa: you would hope that Italy, one of the major European Mediterranean powers, would lead the way, along with France and Spain, in crafting a bold, imaginative European response to the Arab spring. Instead we have pictures of Berlusconi hugging Gaddafi, the Italian state-controlled energy company ENI apparently keeping some of the Libyan dictator's oil and gas revenues flowing, and panic about Tunisian refugees on the Italian island of Lampedusa. Again, Italy is but an extreme version of Europe's confusion. This we can no longer afford.

So, happy 150th birthday, (dis)united Italy. We love you. We feel for you, especially under your present leadership. And we urgently need you back in the vanguard of the great ancient and modern project that we call Europe. After all, you invented it.